Question

what is the common difference in the sequence 25,20,15,10...?

Answer 1

We have a arithmetic sequence: 25, 20, 15, 10...

Tipically, arithmetic sequences can be written in recursive form as:

$a_n=a_{n-1}+d$

where a(n) and a(n-1) are consecutive terms and d is the common difference.

In this case, we can see that each term decreases by 5 units.

Then, we can describe this sequence as:

$a_n=a_{n-1}-5$

which means that d = -5.

Answer: the common difference is d = -5.